* {
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
}
h1 {
  color: #f00;
}
h2 {
  color: #008000;
}
h3 {
  color: #00f;
}
p {
  font-size: 25px;
  color: #008080;
}
.flex-center {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
}
